Today's electric power and transportation systems suffer from a number of drawbacks. Pollution, especially greenhouse gas emissions, is prevalent because approximately half of all electric power generated in the United States is produced by burning coal. Virtually all vehicles in the United States are powered by burning petroleum products, such as gasoline or petro-diesel. It is now widely recognized that human consumption of these fossil fuels is the major cause of elevated levels of atmospheric greenhouse gases, especially carbon dioxide (CO2), which in turn disrupts the global climate, often with destructive side effects. Besides producing greenhouse gases, burning fossil fuels also add substantial amounts of toxic pollutants to the atmosphere and environment. The transportation system, with its high dependence on fossil fuels, is especially carbon-intensive. That is, physical units of work performed in the transportation system typically discharge a significantly larger amount of CO2 into the atmosphere than the same units of work performed electrically.
With respect to the electric power grid, expensive peak power—electric power delivered during periods of peak demand—can cost substantially more than off-peak power. The electric power grid itself has become increasingly unreliable and antiquated, as evidenced by frequent large-scale power outages. Grid instability wastes energy, both directly and indirectly (for example, by encouraging power consumers to install inefficient forms of backup generation).
While clean forms of energy generation, such as wind and solar, can help to address the above problems, they suffer from intermittency. Hence, grid operators are reluctant to rely heavily on these sources, making it difficult to move away from standard, typically carbon-intensive forms of electricity.
The electric power grid contains limited inherent facility for storing electrical energy. Electricity must be generated constantly to meet uncertain demand, which often results in over-generation (and hence wasted energy) and sometimes results in under-generation (and hence power failures).
Distributed electric resources, en masse can, in principle, provide a significant resource for addressing the above problems. However, current power services infrastructure lacks provisioning and flexibility that are required for aggregating a large number of small-scale resources (e.g., electric vehicle batteries) to meet medium- and large-scale needs of power services.
Thus, significant opportunities for improvement exist in the electrical and transportation sectors, and in the way these sectors interact. Fuel-powered vehicles could be replaced with vehicles whose power comes entirely or substantially from electricity. Polluting forms of electric power generation could be replaced with clean ones. Real-time balancing of generation and load can be realized with reduced cost and environmental impact. More economical, reliable electrical power can be provided at times of peak demand. Power services, such as regulation and spinning reserves, can be provided to electricity markets to stabilize the grid and provide a significant economic opportunity. Technologies can be enabled to provide broader use of intermittent power sources, such as wind and solar.
Robust, grid-connected electrical storage could store electrical energy during periods of over-production for redelivery to the grid during periods of under-supply. Electric vehicle batteries in vast numbers could participate in this grid-connected storage. However, a single vehicle battery is insignificant when compared with the needs of the power grid.
Low-level electrical and communication interfaces to enable charging and discharging of electric vehicles with respect to the grid is described in U.S. Pat. No. 5,642,270 to Green et al., entitled, “Battery powered electric vehicle and electrical supply system,” incorporated herein by reference. The Green reference describes a bi-directional charging and communication system for grid-connected electric vehicles, but does not address the information processing requirements of dealing with large, mobile populations of electric vehicles, the complexities of billing (or compensating) vehicle owners, nor the complexities of assembling mobile pools of electric vehicles into aggregate power resources based on grid location, the aggregate power resources being robust enough to support firm power service contracts with grid operators.